package com.lazy.rabbit.demo.rpc;

import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.AMQP.BasicProperties;
import java.util.UUID;

public class RPCClient {

    private Connection connection;
    private Channel channel;
    private String requestQueueName = "rpc_queue";
    private String replyQueueName;
    private QueueingConsumer consumer;

    public RPCClient() throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        connection = factory.newConnection();
        channel = connection.createChannel();

        replyQueueName = channel.queueDeclare().getQueue();
        consumer = new QueueingConsumer(channel);
        channel.basicConsume(replyQueueName, true, consumer);
    }

    public String call(String message) throws Exception{
        String response = null;
        String corrId = UUID.randomUUID().toString();

        BasicProperties props = new BasicProperties.Builder().correlationId(corrId).replyTo(replyQueueName).build();

        channel.basicPublish("", requestQueueName, props, message.getBytes("UTF-8"));

        while(true){
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            if(delivery.getProperties().getCorrelationId().equals(corrId)){
                response = new String(delivery.getBody(), "UTF-8");
                break;
            }
        }

        return response;
    }

    public void close() throws Exception{
        connection.close();
    }

    public static void main(String[] argv){
        RPCClient fibonacciRpc = null;
        String response = null;
        try{
            fibonacciRpc = new RPCClient();

            System.out.println(" [x] Requesting fib(30)");
            response = fibonacciRpc.call("30");
            System.out.println(" [.] Got '" + response + "'");
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            if(fibonacciRpc != null){
                try{
                    fibonacciRpc.close();
                }catch(Exception ignore){
                }
            }
        }
    }
}
